acetate

Also called acetate rayon.a synthetic filament, yarn, or fabric composed of a derivative of the acetic ester of cellulose, differing from viscose rayon in having greater strength when wet and greater sensitivity to high temperatures.

a sheet of clear plastic film fastened over the front of artwork for protection, as an overlay, or the like.

1827, "salt formed by combining acetic acid with a base," from Latin acetum "vinegar" (see acetic) + chemical suffix -ate (3). As a type of synthetic material, it is attested from 1920, short for acetate silk, etc.